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#
# The Python Imaging Library.
# $Id$
#
# image palette object
#
# History:
# 1996-03-11 fl Rewritten.
# 1997-01-03 fl Up and running.
# 1997-08-23 fl Added load hack
# 2001-04-16 fl Fixed randint shadow bug in random()
#
# Copyright (c) 1997-2001 by Secret Labs AB
# Copyright (c) 1996-1997 by Fredrik Lundh
#
# See the README file for information on usage and redistribution.
#
import array
from . import GimpGradientFile, GimpPaletteFile, ImageColor, PaletteFile
class ImagePalette(object):
"""
Color palette for palette mapped images
:param mode: The mode to use for the Palette. See:
:ref:`concept-modes`. Defaults to "RGB"
:param palette: An optional palette. If given, it must be a bytearray,
an array or a list of ints between 0-255 and of length ``size``
times the number of colors in ``mode``. The list must be aligned
by channel (All R values must be contiguous in the list before G
and B values.) Defaults to 0 through 255 per channel.
:param size: An optional palette size. If given, it cannot be equal to
or greater than 256. Defaults to 0.
"""
def __init__(self, mode="RGB", palette=None, size=0):
self.mode = mode
self.rawmode = None # if set, palette contains raw data
self.palette = palette or bytearray(range(256)) * len(self.mode)
self.colors = {}
self.dirty = None
if (size == 0 and len(self.mode) * 256 != len(self.palette)) or (
size != 0 and size != len(self.palette)
):
raise ValueError("wrong palette size")
def copy(self):
new = ImagePalette()
new.mode = self.mode
new.rawmode = self.rawmode
if self.palette is not None:
new.palette = self.palette[:]
new.colors = self.colors.copy()
new.dirty = self.dirty
return new
def getdata(self):
"""
Get palette contents in format suitable for the low-level
``im.putpalette`` primitive.
.. warning:: This method is experimental.
"""
if self.rawmode:
return self.rawmode, self.palette
return self.mode + ";L", self.tobytes()
def tobytes(self):
"""Convert palette to bytes.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(self.palette, bytes):
return self.palette
arr = array.array("B", self.palette)
if hasattr(arr, "tobytes"):
return arr.tobytes()
return arr.tostring()
# Declare tostring as an alias for tobytes
tostring = tobytes
def getcolor(self, color):
"""Given an rgb tuple, allocate palette entry.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(color, tuple):
try:
return self.colors[color]
except KeyError:
# allocate new color slot
if isinstance(self.palette, bytes):
self.palette = bytearray(self.palette)
index = len(self.colors)
if index >= 256:
raise ValueError("cannot allocate more than 256 colors")
self.colors[color] = index
self.palette[index] = color[0]
self.palette[index + 256] = color[1]
self.palette[index + 512] = color[2]
self.dirty = 1
return index
else:
raise ValueError("unknown color specifier: %r" % color)
def save(self, fp):
"""Save palette to text file.
.. warning:: This method is experimental.
"""
if self.rawmode:
raise ValueError("palette contains raw palette data")
if isinstance(fp, str):
fp = open(fp, "w")
fp.write("# Palette\n")
fp.write("# Mode: %s\n" % self.mode)
for i in range(256):
fp.write("%d" % i)
for j in range(i * len(self.mode), (i + 1) * len(self.mode)):
try:
fp.write(" %d" % self.palette[j])
except IndexError:
fp.write(" 0")
fp.write("\n")
fp.close()
# --------------------------------------------------------------------
# Internal
def raw(rawmode, data):
palette = ImagePalette()
palette.rawmode = rawmode
palette.palette = data
palette.dirty = 1
return palette
# --------------------------------------------------------------------
# Factories
def make_linear_lut(black, white):
lut = []
if black == 0:
for i in range(256):
lut.append(white * i // 255)
else:
raise NotImplementedError # FIXME
return lut
def make_gamma_lut(exp):
lut = []
for i in range(256):
lut.append(int(((i / 255.0) ** exp) * 255.0 + 0.5))
return lut
def negative(mode="RGB"):
palette = list(range(256))
palette.reverse()
return ImagePalette(mode, palette * len(mode))
def random(mode="RGB"):
from random import randint
palette = []
for i in range(256 * len(mode)):
palette.append(randint(0, 255))
return ImagePalette(mode, palette)
def sepia(white="#fff0c0"):
r, g, b = ImageColor.getrgb(white)
r = make_linear_lut(0, r)
g = make_linear_lut(0, g)
b = make_linear_lut(0, b)
return ImagePalette("RGB", r + g + b)
def wedge(mode="RGB"):
return ImagePalette(mode, list(range(256)) * len(mode))
def load(filename):
# FIXME: supports GIMP gradients only
with open(filename, "rb") as fp:
for paletteHandler in [
GimpPaletteFile.GimpPaletteFile,
GimpGradientFile.GimpGradientFile,
PaletteFile.PaletteFile,
]:
try:
fp.seek(0)
lut = paletteHandler(fp).getpalette()
if lut:
break
except (SyntaxError, ValueError):
# import traceback
# traceback.print_exc()
pass
else:
raise IOError("cannot load palette")
return lut # data, rawmode
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